Targeted scoring criteria reduce variance in global impressions.

OBJECTIVE This study examined the confounding effect of treatment emergent physical or psychic symptoms on clinical global impression (CGI) ratings in CNS trials and examined the benefit of targeted scoring criteria on clarifying ratings and reducing scoring variance. METHODS Twenty-four raters participating in an investigator meeting training session scored a series of scripted CGI scenarios that included treatment emergent symptoms. RESULTS The addition of treatment emergent gastrointestinal (GI) symptoms or anxiety symptoms significantly changed the rating of clinical global improvement and caused a broad CGI-improvement (CGI-I) scoring variance reflecting scoring ambiguity amongst these raters. Re-rating after a presentation of well-defined criteria that addressed these scoring issues narrowed the variance and significantly improved inter-rater reliability. CONCLUSIONS It is clear that CNS trials must define scoring criteria for global ratings prior to the initiation of a study to assure ratings consistency. The actual definition of global must be study-specific and may depend upon the targeted symptoms of interest and mechanism of drug action. The targeted criteria that define global must be included in all published reports about the trial.